Best: Last year's smash trailer. It was refreshing to see a truly competent first trailer, by Nintendo no less, for a game which would create this much buzz. When the competitors are squabbling over new consoles Nintendo brings out smash to resounding applause and does the Megaman reveal right there, and Wii Fit Trainer's fantastic reveal... In fact the whole trailer had so much soul and quality, it just really made me feel excited for the game in a way that has been weining significantly since the smash direct got me worried...
I'll be honest I didn't really like Brawl's trailers, it just wasn't very good in my opinion, and Snake was way too left field to even be funny, even with a well designed reveal. Given how the game turned out in the end I guess it was a good indicator of what was to come.
Infact the entire Direct last year rocked, and probably because it was a direct... I'm a real advocate of direct advertising that way, and far preferred seeing the footage for myself, though that's probably my profession talking.
Worst: Nintendo Land Fireworks... Wii Music was a worse presentation, but Nintendo Land was that last minute 'surprise', it got my hopes up for fireworks that would look mediocre on the N64... not good Nintendo, not good.
Outside of Nintendo I've gotta say FFXV last year, I'm not the biggest fan of FF (I'm more into DQ obviously), but I do respect it's attempts at trying new things in the genre... but last year they made it look like a cover shooter, and even with newer trailers it still looks like they ditched the jRPG for generic God of War/COD rip-off street... either way I wouldn't get the game after the turd that was XIII, and to a lesser extent XII, but the trailer ate those last few scraps of respect I had for the series... luckily Bravely Default just remade V, the best in the series, to make a new franchise I can love, possibly even more than DQ if the series gets better rather than just newer.